Excessive distributor gear wear from billet cam
07-24-2012, 09:39 AM
#41
Research I have done online indicates that the Comp Cams composite distributor gear may be worth a try. Kind of pricey, but what isn't with a boat. If it gets shredded, I would think that this material would be easier on parts if it got ingested than metal would be. It appears that some people are having good luck with them, and it is what engine builder recommends.
I am going to get some kind of pattern dye to check the wear pattern before I run it. May have to find a way to get the distributor to sit a bit lower, although I don't know of a way to do that besides a slip collar or mill down the distributor body where it rests on the intake. Also going to modify the bottom of the distributor for more oiling on the gears. Will liberally coat everything with high pressure moly assembly lube before startup.
I am wondering if I should consider running a slightly lighter weight oil. I am running Castrol 20W-50 conventional oil right now. Thinking about something on the order of 15W-50 or 15W-40. Merc oil is a possibility. Suggestions?
I am going to get some kind of pattern dye to check the wear pattern before I run it. May have to find a way to get the distributor to sit a bit lower, although I don't know of a way to do that besides a slip collar or mill down the distributor body where it rests on the intake. Also going to modify the bottom of the distributor for more oiling on the gears. Will liberally coat everything with high pressure moly assembly lube before startup.
I am wondering if I should consider running a slightly lighter weight oil. I am running Castrol 20W-50 conventional oil right now. Thinking about something on the order of 15W-50 or 15W-40. Merc oil is a possibility. Suggestions?
07-24-2012, 10:17 AM
#42
Registered
I run a billit cam with a composite dist. gear. I think when you get the right contact patch on the dist. gear you wont have any more problems. As far as the oil I use stright 40 wt. 70lbs at cruse speed and 40lbs. at idle. No problems with dist. gear wear.
07-24-2012, 11:04 PM
#43
Well, the other oil filter looked much better. There was a little bit of metal that was probably from the dist gear, but no signs of bearing material.
However, now I have a bigger problem. I turned the oil pump drive with a screw driver, and it feels very rough. In fact, it felt like it wants to lock up at a couple of points of the rotation. I'm not sure if the particles of the gear ruined the pump, or if it was the pump going bad that wore the gear. I guess I will be pulling a motor to find out.
However, now I have a bigger problem. I turned the oil pump drive with a screw driver, and it feels very rough. In fact, it felt like it wants to lock up at a couple of points of the rotation. I'm not sure if the particles of the gear ruined the pump, or if it was the pump going bad that wore the gear. I guess I will be pulling a motor to find out.
07-25-2012, 08:13 AM
#45
Exactly, EZ. It's the chicken or the egg theory - did the dist gear go south because of the oil pump, or did the oil pump pick up a bunch of debris from the dist gear. I am betting on the first theory - the pump either went bad or managed to suck something up that FUBAR'ed the gears in it. The $100,000 question is what did it suck up and where did it come from. I don't think these pumps have a habit of just failing on their own.
07-26-2012, 12:01 PM
#48
I have been doing some searching on OSO for threads about oil pump recommendations, and I came across a couple of threads that caution against excessive welding for the oil pickup. Sure wish I had seen this before, because I bet that is what happened to my pump! I found that the weld on the pickup on my old 454 had broken loose and the pickup was loosely swiveling back and forth, so I asked a welder friend to put a good weld on the new pump. He welded all the way around the diameter of the pickup instead of just a tack weld. I am betting that this warped the cover and led to the gears galling. I'll find out soon enough. I saw a couple of recommendations on welding a strap onto the pickup that goes through one of the cover bolts. Anyone want to comment on this method? Is this a good way to go?
Also, a friend of mine has a stock HP500 pump that has very low hours on it. He switched to a HV pump because he was supercharged at the time and was worried about the oil pressure reading low (in the 40's at speed). Turns out that he was also running the low pressure spring in this pump. Would this pump work fine with the correct high pressure spring installed? My motor is normally aspirated, running a sandwich adapter instead of remote oil filter, with #10 lines going to oil cooler.
Also, a friend of mine has a stock HP500 pump that has very low hours on it. He switched to a HV pump because he was supercharged at the time and was worried about the oil pressure reading low (in the 40's at speed). Turns out that he was also running the low pressure spring in this pump. Would this pump work fine with the correct high pressure spring installed? My motor is normally aspirated, running a sandwich adapter instead of remote oil filter, with #10 lines going to oil cooler.
08-17-2012, 01:07 PM
#49
MarineKinetics
Platinum Member
Budman
Going on the assumption that your camshaft is a genuine GM steel core it would be made from a 51xx alloy which is induction hardened. While technically it is a steel billet core, there is a difference between this core and a core that is traditionally referred to as a “billet” core. The billet cores we use are all 86xx alloy which are carburized. A carburized heat treat is significantly deeper than induction hardened treat. That’s an important factor when considering regrinding a camshaft.
It would appear your gear failure on the induction hardened core could be either of the following elements.
1) The gear you used was not a Melonized gear.
2) There was an improper wear pattern on the cam after the first use which caused premature degradation of the new gear. If that’s the case there is the potential to continue to fail any additional gears you put back on the cam.
You may also be looking at some secondary issues down the road from regrinding an induction hardened camshaft. If the hardened layer of the camshaft has been compromised during the regrinding process this could lead to a failure at some point down the road. When the hardened layer becomes too thin you run the risk of penetration as the substrate layer beneath it begins to yield. As it does so, the stresses can result in spalling or failing a camshaft lobe at some point down the road.
We are currently using a gear manufactured for us that is hardened steel, treated, gear compatible with cast/induction hardened/carburized cores.
Bob
Going on the assumption that your camshaft is a genuine GM steel core it would be made from a 51xx alloy which is induction hardened. While technically it is a steel billet core, there is a difference between this core and a core that is traditionally referred to as a “billet” core. The billet cores we use are all 86xx alloy which are carburized. A carburized heat treat is significantly deeper than induction hardened treat. That’s an important factor when considering regrinding a camshaft.
It would appear your gear failure on the induction hardened core could be either of the following elements.
1) The gear you used was not a Melonized gear.
2) There was an improper wear pattern on the cam after the first use which caused premature degradation of the new gear. If that’s the case there is the potential to continue to fail any additional gears you put back on the cam.
You may also be looking at some secondary issues down the road from regrinding an induction hardened camshaft. If the hardened layer of the camshaft has been compromised during the regrinding process this could lead to a failure at some point down the road. When the hardened layer becomes too thin you run the risk of penetration as the substrate layer beneath it begins to yield. As it does so, the stresses can result in spalling or failing a camshaft lobe at some point down the road.
We are currently using a gear manufactured for us that is hardened steel, treated, gear compatible with cast/induction hardened/carburized cores.
Bob
08-17-2012, 01:30 PM
#50
Platinum Member
Platinum Member
Budman
Going on the assumption that your camshaft is a genuine GM steel core it would be made from a 51xx alloy which is induction hardened. While technically it is a steel billet core, there is a difference between this core and a core that is traditionally referred to as a “billet” core. The billet cores we use are all 86xx alloy which are carburized. A carburized heat treat is significantly deeper than induction hardened treat. That’s an important factor when considering regrinding a camshaft.
It would appear your gear failure on the induction hardened core could be either of the following elements.
1) The gear you used was not a Melonized gear.
2) There was an improper wear pattern on the cam after the first use which caused premature degradation of the new gear. If that’s the case there is the potential to continue to fail any additional gears you put back on the cam.
You may also be looking at some secondary issues down the road from regrinding an induction hardened camshaft. If the hardened layer of the camshaft has been compromised during the regrinding process this could lead to a failure at some point down the road. When the hardened layer becomes too thin you run the risk of penetration as the substrate layer beneath it begins to yield. As it does so, the stresses can result in spalling or failing a camshaft lobe at some point down the road.
We are currently using a gear manufactured for us that is hardened steel, treated, gear compatible with cast/induction hardened/carburized cores.
Bob
Going on the assumption that your camshaft is a genuine GM steel core it would be made from a 51xx alloy which is induction hardened. While technically it is a steel billet core, there is a difference between this core and a core that is traditionally referred to as a “billet” core. The billet cores we use are all 86xx alloy which are carburized. A carburized heat treat is significantly deeper than induction hardened treat. That’s an important factor when considering regrinding a camshaft.
It would appear your gear failure on the induction hardened core could be either of the following elements.
1) The gear you used was not a Melonized gear.
2) There was an improper wear pattern on the cam after the first use which caused premature degradation of the new gear. If that’s the case there is the potential to continue to fail any additional gears you put back on the cam.
You may also be looking at some secondary issues down the road from regrinding an induction hardened camshaft. If the hardened layer of the camshaft has been compromised during the regrinding process this could lead to a failure at some point down the road. When the hardened layer becomes too thin you run the risk of penetration as the substrate layer beneath it begins to yield. As it does so, the stresses can result in spalling or failing a camshaft lobe at some point down the road.
We are currently using a gear manufactured for us that is hardened steel, treated, gear compatible with cast/induction hardened/carburized cores.
Bob
